In another paper1 it was pointed out that the introduction of various intracutaneous tests and Huddleson's opsonocytophagic reaction, while providing a new approach to the study of brucellosis, has raised certain confusing problems which have not yet been solved. It seems probable that these tests, together with the agglutination reaction, are of service in indicating whether or not the tissues have been invaded by Brucella at one time or another, in this respect affording information of essentially the same value and limitations as the tuberculin test in suspected tuberculosis or the Wassermann test in syphilis. Doubt has properly been cast on the infallibility of Huddleson's diagnostic criteria, however, by the facts that brucellosis, a common and endemic disease, may be latent or asymptomatic and that the finding of positive tests may thus not indicate active disease but merely coincidental infection of no significance.